reamer

Abstract

To improve also processed hole accuracy by restraining cut-refuse entanglement and a deficit-breakage of a cutting edge to a reamer.SOLUTION: A reamer having a biting cutting edge 7a, an outer peripheral cutting edge 8a and a scooping surface 9 continuing to these in an axial directional tip part has a plurality of outer peripheral cutting edges 8a in the circumferential direction, and has a tooth space 5, a margin 8b and an outer peripheral flank 8c between a plurality of these outer peripheral cutting edges 8a, and the margin 8b is formed by exceeding a base end side end point part 6 of the tooth space, and a neck 3 is not arranged in a tooth space 5-formed part, and the outer peripheral flank 8c extends up to the base end side end point part 6 of at least the tooth space.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a reamer.

Background Art

[0002] Since chips are generated inside the hole by a reamer, depending on the chip discharge situation, problems such as the chips damaging the inner wall of the hole, getting entangled with the reamer, clogging the flute and causing the cutting edge to be damaged or broken may occur. In order to solve the above problems, a tool with a breaker is known as the prior art (see, for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The problem to be solved by the present invention is to provide a reamer that suppresses chip entanglement with the reamer and damage or breakage of the cutting edge, and also improves the machining hole accuracy, even without a breaker known as the prior art.

Means for Solving the Problems

[0005] The present invention has been made to solve the above problems, and is a reamer having a cutting edge and an outer peripheral cutting edge at the axial tip end and a rake face continuous therewith, having a plurality of the outer peripheral cutting edges in the circumferential direction, having a blade groove, a margin, and an outer peripheral relief face between the plurality of the outer peripheral cutting edges, the margin being formed beyond the end point portion on the proximal end side of the blade groove, no neck being provided in the portion where the blade groove is formed, and the outer peripheral relief face extending at least to the end point portion on the proximal end side of the blade groove.

[0006] Furthermore, the cutting edge may have a curved shape bulging toward the tip end side.

[0007] Furthermore, there is a face connecting the margin and the outer peripheral relief face and the end face on the tip end side, and further having a cutting relief face forming the cutting edge at the tip end portion in the rotation direction, and the cutting relief face may have a shape in which the distance from the reamer axis gradually decreases as it goes rearward in the rotation direction.

Effects of the Invention

[0008] Since the margin (partial cylindrical surface) is formed beyond the end point portion on the proximal end side of the blade groove and no neck (constricted portion between the blade portion and the shank portion) is provided in the portion where the blade groove is formed, it is possible to suppress chips from winding around the reamer body. Further, since the outer peripheral relief face extends at least to the end point portion on the proximal end side of the blade groove, the coolant can enter well into the blade portion, and a chip escape space can be secured.

[0009] Furthermore, by making the cutting edge have a curved shape bulging toward the tip end side, the chips can be gradually thinned, so that the chip discharge performance can be further improved. Also, by making the cutting edge have a curved shape, the stress during cutting is dispersed, and chipping and breakage can be suppressed. In the case of a straight cutting edge, the edge portion wears rapidly at the initial stage of machining, so the hole accuracy at the initial stage of machining may not be stable. However, by making the cutting edge have a curved shape, it becomes a state of pseudo wear, and the hole accuracy is stable from the initial stage of machining. Also, an effect of suppressing burrs at the inlet and outlet of the machined hole can be obtained.

[0010] Furthermore, the feed-engaging relief surface is shaped such that the distance from the reamer axis gradually decreases as it goes rearward in the rotational direction. This ensures that when engaging with the pilot hole, the entire feed-engaging relief surface does not contact the inner wall of the pilot hole, preventing an increase in cutting resistance and suppressing troubles such as defects and breakages.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Mode for Carrying Out the Invention

Examples

[0012] Figures 1 and 2 are a perspective view and a front view of Example 1 of the present invention. As shown in Figures 1 and 2, in the reamer of Example 1, a cutting edge portion 2 is provided on the axial tip side of a straight bar-shaped reamer body 1, and a shank 4 that is gripped by chucking is provided on the base end side. In this reamer, the cutting diameter size is, for example, 0.3 to 25 mm in diameter.

[0013] Also, at least the cutting edge portion 2 of the reamer is formed from a single material such as cemented carbide, cermet, high-speed tool steel, etc. On the other hand, the shank 4 is a material different from the cutting edge portion 2 and may be brazed and joined.

[0014] And, as shown in Figure 1, the reamer is used by rotating it clockwise when viewed from the base end side to the tip side around the reamer axis C.

[0015] As shown in Figures 2 and 3, on the cutting edge portion 2, an outer peripheral cutting edge 8a is formed by a plurality of cutting edge grooves 5, a margin (partial cylindrical surface) 8b, and an outer peripheral relief surface 8c along the circumferential direction. Here, the cutting edge grooves 5, the margin 8b, and the outer peripheral cutting edge 8a are formed to extend linearly along the reamer axis C.

[0016] Figure 6 is a front view in the case of a sticking taper (linear sticking cutting edge 7a) with a neck in Comparative Example 1. As shown in Figure 6, in the case of a shape having a neck 3, when the neck 3 is inserted into the machining hole, it was found that, depending on the workpiece material and cutting conditions, chips would wrap around the neck 3 and the cutting edge portion 2.

[0017] In such a case, as shown in FIGS. 1 and 2 of Example 1, the margin 8b extends beyond the end portion 6 on the proximal side of the flute, and is directly connected to the shank 4 gripped by chucking or is connected via a stepped portion, and a neck 3 shown in FIG. 6 is not provided in the portion related to the flute 5, thereby suppressing chips from winding around the reamer body 1.

[0018] Normally, as shown in Comparative Example 2 of FIG. 7, the outer peripheral relief surface 8c often extends up to the range where the flute 5 is parallel to the reamer axis C (the apex position of the grinding wheel for machining the flute 5), but in Example 1, it extends up to the end portion 6 on the proximal side of the flute. Since the neck 3 is not provided in the portion related to the flute 5 on the reamer axis C and the outer peripheral relief surface 8c extends at least up to the end portion 6 on the proximal side of the flute, it is possible to suppress chips from winding around the reamer body 1, improve the entry of coolant into the cutting edge 2, and secure a relief space for chips.

[0019] As shown in FIG. 3, since the outer peripheral relief surface 8c is ground with the grinding wheel R16, for example, when a φ75 mm grinding wheel is used, as viewed from the left side view, a machining surface with a radius of R37.5 mm of the grinding wheel is formed on the shank 4 side. The end of the outer peripheral relief surface 8c can be made perpendicular to the reamer axis C or angled depending on the angle at which the grinding wheel is swung. As shown in FIG. 2, the angle σ between the reamer axis C and the end portion of the outer peripheral relief surface is 30° to 90° (specifically 60°).

Example

[0020] The reamer of this Example 2 is basically the same as that of Example 1. Therefore, in the following, the description will focus on the differences between the two, and the description of the same parts will be omitted. Also, the parts corresponding to Example 1 will be described with the same reference numerals.

[0021] 4 and 5 are enlarged views and perspective views of the chamfer portion of Example 1 of the present invention. As shown in FIGS. 8 and 9, Example 2 replaces the linear chamfer cutting edge 7a formed by the chamfer flank 7b in Example 1 with a curved chamfer bulging toward the tip. The chamfer flank 7b connects the margin 8b and the peripheral flank 8c with the tip-side end face 15, forming the chamfer cutting edge 7a at the tip in the rotational direction. Examples of the curved chamfer bulging toward the tip include a circular arc, an elliptical arc, and a parabolic arc. Specifically, the chamfer cutting edge 7a of Example 2 bulges outward relative to the reamer axis C, more so than the linear chamfer cutting edge 7a of Example 1.

[0022] By making the cutting edge 7a formed by the cutting relief surface 7b curved (circular arc, elliptical arc, parabolic, etc.), the thickness of the chips gradually becomes thinner, and in addition to the effect of Example 1, the effect of chip discharge can be further improved.

[0023] The cutting edge 7a does not necessarily have to be curved; a curved cutting edge 7a may be formed following a straight cutting edge 7a. As shown in FIG. 8, for example, the curvature radius of the curved cutting edge 7a following the straight cutting edge angle γ of 45° to 90° is 0.2 to 2.0 mm. In this case, it is preferable for the cutting edge 7a to bite into the pilot hole at a curved position. By reducing the curvature radius, the axial distance of the cutting edge 7a becomes shorter, making it possible to ream not only through holes, but also blind holes and blind holes close to the bottom.

[0024] Furthermore, the curved cutting edge 7a is not a so-called chamfered shape obtained by simply rotating a curve around the reamer axis C, but is formed by a cutting edge relief surface 7b that follows the curved cutting edge 7a, just like the straight cutting edge 7a, and the cutting edge relief surface 7b is shaped so that the distance from the reamer axis C gradually decreases as it moves rearward in the direction of rotation.

[0025] Fig. 10(a) is a diagram of the tooth engagement chamfered shape of the conventional structure. When the distance between the leading end in the rotational direction of the tooth engagement relief surface 7b and the reamer axis C is r1, and the distance between the trailing end in the rotational direction of the tooth engagement relief surface 7b and the reamer axis C is r2, the relationship is r1 = r2. In contrast, Fig. 10(b) is a diagram of the tooth engagement R relief surface shape of Example 2. In the tooth engagement relief surface 7b of Example 2, the relationship is r1 > r2. Specifically, in the tooth engagement relief surface 7b of Example 2, a configuration is adopted in which a perpendicular line L2 to a straight line L1 connecting the leading end in the rotational direction and the reamer axis C forms an angle η with the axial leading edge line L3 of the tooth engagement relief surface 7b. This angle η is, for example, 8° to 35°. By setting r1 > r2 as in Example 2, when engaging with the pilot hole, the entire tooth engagement relief surface 7b does not contact the inner wall of the pilot hole, preventing an increase in cutting resistance and suppressing troubles such as defects and breakages.

[0026] The reamers of Example 2 and Comparative Example 1 in Fig. 6 were fabricated from cemented carbide with a diameter of φ6.0 mm, coated with an AlCr-based coating, and drilling was performed under the following conditions.

[0027] Workpiece material: SUS304 Pilot drill: Cemented carbide coated drill φ5.9 Rotational speed: 1590 min -1 Cutting speed: 30 m / min Feed per revolution: 0.1 mm / rev Feed rate: 159 mm / min Hole depth: 18 mm (through-hole machining)

[0028] As a result, in Example 2, as shown in Fig. 11, there was no chip winding around the reamer body 1, and 1000 hole machinings were possible, and continuous machining was possible. The machined hole diameter was also a high-precision hole through which a pin gauge of the same diameter as the actual reamer diameter passed. In the tapered tooth engagement (linear tooth engagement cutting edge 7a)·necked shape of Comparative Example 1 shown in Fig. 6, after 100 hole machinings, chip breakage occurred at 3 out of 6 cutting edges, and as shown in Fig. 12, chips wound around the reamer body 1, so the machining was stopped.

[0029] FIG. 13 is a comparison graph of the machining hole accuracy between the R-tooth (curved tooth cutting edge 7a) and neckless shape of Example 2 and the tapered tooth (linear tooth cutting edge 7a) and necked shape of Comparative Example 1 shown in FIG. 6. Although the results are also shown in Table 1 below, Example 2 has better hole accuracy than Comparative Example 1. The tool life of Example 2 was extended and the hole accuracy was improved because there was no chip wrapping around the reamer body 1, the coolant entered the cutting edge 2 well, the stress during tooth engagement was dispersed by the curved tooth engagement, defects and breakage could be suppressed, and the chip discharge property was good.

[0030]

Table 1

Example

[0031] The reamer of this Example 3 is basically the same as those of Example 1 and Example 2. Therefore, in the following, the description will focus on the differences between the two, and the description of the same parts will be omitted. Also, the same reference numerals will be given to the corresponding parts as in Example 1 for description.

[0032] FIG. 14 is a left side view of Example 3 of the present invention, and FIGS. 15 and 16 are partial enlarged views ((a) left side view and (b) front view) of the same Example 3 and a perspective view of the breaker portion.

[0033] As shown in FIGS. 15 and 16, the rake face 9 is formed continuously from a recess 10a recessed on the side opposite to the rotation direction, continuous with the tooth cutting edge 7a and the outer peripheral cutting edge 8a. The breaker recess 10a forms a recess due to the angular difference between the first rake angle α and the second rake angle β. The end portion on the rotation axis side of the breaker 10a (that is, the open end portion on the radially inner side) is linear, and is inclined at an inclination angle θ so as to face the outer peripheral cutting edge 8a from the tip side toward the base end side (that is, away from the reamer axis C). Due to this inclination, the flow of chips can be blocked, and the effect of dividing the chips is enhanced.

[0034] Further, it is preferable that the breaker angle 10c, which is the corner between the breaker recess 10a and the breaker edge portion 10b, has an arc shape. By making it an arc shape, the curl of the chips can be reduced.

Embodiment

[0035] FIG. 17 is a (a) left side view and (b) front view of Example 4 of the present invention. As shown in FIG. 17, a breaker can be added to the shape with a bottom edge formed by the bottom edge second relief 11, the bottom edge third relief 12, and the gash 13. If there is a bottom edge, it is also effective for blind holes and pocket holes.

[0036] The reamers of the above-described respective embodiments may have an oil hole.

[0037] The reamers of the above-described respective embodiments had six cutting edges, but they may have any number of cutting edges. Further, the flute 5 is not limited to a straight flute and may be a helical flute, and the split angle of the flute may be either equally divided or unequally divided.

[0038] The tip shape of the tool may have a hole center or a convex center necessary for manufacturing.

[0039] As shown in FIG. 1, the above-described respective embodiments are used by rotating clockwise when viewed from the base end side to the tip end side around the reamer axis C. However, a shape obtained by inverting the content of the present invention may also be used. In that case, it is used by rotating counterclockwise when viewed from the base end side to the tip end side around the reamer axis C.

[0040] When a coating is applied to the cutting edge portion 2 of the above-described respective embodiments, advantages such as increasing the tool life, increasing the machining efficiency, improving the surface roughness of the machined hole, and improving the chip discharge property can be obtained. Methods for generating a coating film include CVD (Chemical Vapor Deposition) and PVD (Physical Vapor Deposition). For example, raw materials such as Ti-based, Cr-based, DLC, and diamond are ionized and coated. The coating film type and film thickness are selected according to the application, and characteristics such as wear resistance, heat resistance, impact resistance, low friction, and non-adhesion can be obtained.

[0041] Coating improves the tool performance, but since the cutting edges (such as the engaging cutting edge 7a or the outer peripheral cutting edge 8a, etc.) become rounded, the sharpness of the blade deteriorates. Therefore, before forming the breaker (recess) 10a in the reamer, the cutting edge portion 2 is coated, and by forming the breaker (recess) 10a after coating the cutting edge portion 2, the edges of the engaging cutting edge 7a and the outer peripheral cutting edge 8a can be sharpened, leading to an improvement in the cutting performance.

[0042] Therefore, the following method for manufacturing a reamer is also an aspect of the present invention.

[0043] That is, the method for manufacturing a reamer according to the present invention has an engaging cutting edge 7a, an outer peripheral cutting edge 8a, and a rake face 9 continuous therewith at the axially leading end portion, and the rake face 9 is formed from a recess recessed on the side opposite to the rotational direction continuously with the engaging cutting edge 7a and the outer peripheral cutting edge 8a, and has a breaker for breaking chips cut by the engaging cutting edge 7a, and an end portion of the breaker on the rotational axis side is inclined so as to face the outer peripheral cutting edge 8a as it goes from the leading end side to the base end side. In the method for manufacturing a reamer, before forming the breaker recess 10a in the rake face 9, the engaging cutting edge 7a, the outer peripheral cutting edge 8a, and the rake face 9 are coated, and after applying the coating, the breaker recess 10a is formed.

Explanation of reference numerals

[0044] C ··· Reamer axis 1 ··· Reamer body 2 ··· Cutting edge portion 3 ··· Neck (constricted portion between the cutting edge portion and the shank portion) 4 ··· Shank 5 ··· Flute 6 ··· End point portion on the base end side of the flute 7a ··· Engaging cutting edge 7b ··· Engaging relief face 8a ··· Outer peripheral cutting edge 8b ··· Margin (partial cylindrical surface) 8c ··· Outer peripheral relief face 8d ··· Cylindrical surface on the same plane as the margin 9 ··· Scoop surface 10a ··· Breaker recess 10b ··· Breaker edge part 10c ··· Breaker angle 11 ··· Second flank relief of the bottom edge 12 ··· Third flank relief of the bottom edge 13 ··· Gash 14 ··· Center hole 15 ··· Tip-side end face 16 ··· Wheel radius R L1 ··· Straight line connecting the tip in the rotation direction and the reamer axis C L2 ··· Perpendicular line to L1 L3 ··· Ridge line on the axial tip side of the cutting relief surface η ··· Angle formed by L2 and L3 σ ··· Angle between the axis and the end point of the outer peripheral relief surface α ··· First rake angle β ··· Second rake angle γ ··· Cutting angle (angle between the axis and the cutting edge) θ ··· Angle between the axis and the breaker

Claims

【Claim 1】 A reamer having a cutting edge that bites at the axial tip, an outer peripheral cutting edge, and a rake face continuous therewith, having a plurality of the outer peripheral cutting edges in the circumferential direction, and having a cutting groove, a margin, and an outer peripheral relief face between the plurality of the outer peripheral cutting edges, the margin is formed beyond the end portion on the proximal end side of the cutting groove in the direction along the reamer axis, no neck is provided in the portion where the cutting groove is formed, the outer peripheral relief face extends at least to the end portion on the proximal end side of the cutting groove in the direction along the reamer axis, a face connecting the margin and the outer peripheral relief face and the end face on the tip side, further having a biting relief face that forms the biting cutting edge at the tip portion in the rotation direction, the biting relief face has a shape in which the distance from the reamer axis gradually decreases as it goes backward in the rotation direction, the biting cutting edge has a linear biting cutting edge and a curved biting cutting edge that bulges toward the tip side and is formed continuously with the linear biting cutting edge, the reamer.

Images